Last three millennia Earth’s Magnetic field strength in Mesoamerica and southern United States: Implications in geomagnetism and archaeology

Goguitchaichvili, Avto; García-Ruiz, Rafael; Pavón‐Carrasco, F. J.; Contreras, Juan; Arechalde, Ana María Soler; Urrutia‐Fucugauchi, J.

doi:10.1016/j.pepi.2018.04.003

Cited by 28 publications

(25 citation statements)

References 62 publications

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“…Mahgoub et al (2019a) curve differs by the inversion process based on the full geomagnetic vector taking into account directional and intensity data at the same time. Whereas Mahgoub et al (2019a) curve is close to our, although smoother, with an intensity maximum at the second century BCE, the curve of Goguitchaichvili et al (2018) shows a minimum at this period. This inconsistency is likely related to the differences in the selection of the input dataset.…”

Section: Comparison With Mexican Master Curves and Global Geomagneticsupporting

confidence: 69%

“…Two other secular variation curves of the intensity in Mexico have recently been published by Goguitchaichvili et al (2018) and Mahgoub et al (2019a), both calculated using a bootstrap approach (Thébault & Gallet, 2010) after different data selection (Figure 6a). Mahgoub et al (2019a) curve differs by the inversion process based on the full geomagnetic vector taking into account directional and intensity data at the same time.…”

Section: Comparison With Mexican Master Curves and Global Geomagneticmentioning

confidence: 97%

“…This clearly underlines the necessity of full vector determination for a good resolution of the secular variation of the Earth Magnetic field. (Goguitchaichvili et al, 2018;Mahgoub et al, 2019aMahgoub et al, , 2019b and the predictions of global models BIGMUDI4k.1 (Arneitz et al, 2019), CALS10k.2 (Constable et al, 2016), COV-ARCH, and COV-LAKE (Hellio & Gillet, 2018). (b) Comparison of the curve of the Virtual Axial Dipole Moment (VADM) in Mexico with data from north-western USA (Champion, 1980), the East Pacific Ridge (Gee et al, 2000;Pick & Tauxe, 1993) and Hawaii (Cromwell et al, 2018;Mankinen & Champion, 1993;Pressling et al, 2006;Pressling et al, 2007;Tema et al, 2017;Valet et al, 1998).…”

Section: Comparison With Other Regional Recordsmentioning

confidence: 99%

“…In Mexico, a large number of archaeomagnetic studies on baked clays or lava flows have been published in the last 10 years (e.g., Fanjat et al, 2013;Mahgoub et al, 2017;Mahgoub et al, 2019bMahgoub et al, , 2019aMahgoub et al, 2019aMahgoub et al, , 2019bPétronille et al, 2012;Rodriguez-Ceja et al, 2009;Rodriguez-Trejo et al, 2019;Terán et al, 2016), but a recent critical analysis of the Mexican dataset showed that around 70% of these data cannot be considered as high quality, according to basic selection criteria. Two local secular variation curves have been recently proposed using only Mexican data (Mahgoub et al, 2019a) or also some from the southwestern United States (Goguitchaichvili et al, 2018). The significant differences between the two curves point out that the resolution of the secular variation during the first millennium BCE is still not good.…”

Section: Introductionmentioning

confidence: 99%

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Secular Variation of the Intensity of the Geomagnetic Field in Mexico During the First Millennium BCE

Hervé

Perrin

Alva‐Valdivia

et al. 2019

Geochem Geophys Geosyst

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In Western Eurasia, the first millennium BCE is characterized by the fastest secular variation of the Earth Magnetic Field observed over the last millennia and by a geomagnetic anomaly centered on the Middle East. On the global scale, the variation of the dipolar field during this period remains poorly constrained because of the lack of data in other geographical areas. Here, we presented 23 new mean archaeointensity data on ceramic sherds dated between 1500 BCE and 200 CE from Chalcatzingo archaeological site in Central Mexico. Archaeointensities were determined using the classical Thellier-Thellier protocol with corrections for TRM anisotropy and cooling rate effects. Our work doubles the number of high-quality archaeointensity data in Mexico during the considered period. Using a Bayesian approach, a new secular variation curve was calculated at Mexico City between 1500 BCE and 200 CE after selection of Mexican archaeointensity data. After a period of oscillations of the intensity between 20 and 40 μT from 1500 to 300 BCE, the curve shows a large maximum`~65 μT in the second century BCE. The corresponding VADM varied between~4.0 and~11.0 × 10 22 Am 2 , which highlights further that the intensity of the geomagnetic field could vary at regional scale over a larger range as previously thought. However, this amplitude variation may be overestimated, as it does not take into account the fast directional variation observed at this time.Plain Language Summary Archaeological baked clays are the best material to reconstitute the past secular variation of the Earth magnetic field, because they acquired a generally stable thermoremanent magnetization usually parallel and proportional to the ambient field at the time of their baking. Global modeling of the geomagnetic field requires a spatial and temporal distribution of data as homogeneous as possible, which is still not the case yet. In spite of its rich archaeological heritage, high-quality archaeointensity data are still very few in Mexico. The present study focuses on pottery sherds dated between 1500 BCE and 200 CE from Chalcatzingo archaeological site in Central Mexico. We obtained 21 new mean archaeointensities, which almost doubles the high-quality Mexican dataset for this period. The new secular variation Mexican curve exhibits oscillations of the intensity between 20 and 40 μT from 1500 to 300 BCE, before a large maximum~65 μT in the second century BCE. This work will help to have a better knowledge of the variation of the dipolar geomagnetic field during the first millennium BCE, when the fastest secular variation over the last millennia was reported in the Middle East ("geomagnetic spikes").

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Section: Comparison With Mexican Master Curves and Global Geomagneticsupporting

confidence: 69%

Section: Comparison With Mexican Master Curves and Global Geomagneticmentioning

confidence: 97%

Section: Comparison With Other Regional Recordsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Secular Variation of the Intensity of the Geomagnetic Field in Mexico During the First Millennium BCE

Hervé

Perrin

Alva‐Valdivia

et al. 2019

Geochem Geophys Geosyst

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“…In order to obtain a good representation for the variation of the archaeointensity for the last two millennia in the North-West of Africa, we tested two methods to obtain a representative PSV curve: a smoothing spline fit and a stochastic modelling approach 35 . For the smoothing spline fit (SSF) we applied the bootstrap method on continuous temporal penalized cubic B-spline interpolators 32 as it was previously applied in the the study of Goguitchaishvili et al 20 , i.e. using a L2-norm for the measure of misfits instead of the Huber norm used in Thebault et al 32 .…”

Section: Setting Up Of the Reference Curvesmentioning

confidence: 99%

Novel insights on the geomagnetic field in West Africa from a new intensity reference curve (0-2000 AD)

Kapper

Serneels

Panovska

et al. 2020

Sci Rep

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The geomagnetic field variations on the continent of Africa are still largely undeciphered for the past two millennia. In spite of archaeological artefacts being reliable recorders of the ancient geomagnetic field strength, only few data have been reported for this continent so far. Here we use the Thellier-Coe and calibrated pseudo-Thellier methods to recover archaeointensity data from Burkina Faso and Ivory Coast (West Africa) from well-dated archaeological artefacts. By combining our 18 new data with previously published data from West Africa, we construct a reference curve for West Africa for the past 2000 years. To obtain a reliable curve of the archaeointensity variation, we evaluate a penalized smoothing spline fit and a stochastic modelling method, both combined with a bootstrap approach. Both intensity curves agree well, supporting the confidence in our proposed intensity variation during this time span, and small differences arise from the different methodologies of treating data and uncertainties. Two prominent peaks at around 740 AD and 1050 AD appear to be common in ours and several reference curves from other locations, indicating a general westward movement from China to Hawaii of a rather stable feature of the geomagnetic field. However, independent smaller peaks that do not correlate in different locations may hint to localized expressions of the geomagnetic field as a result of temporarily varying non-dipole sources.Archaeological artefacts have already in the 1930s been proven to be excellent recorders of the geomagnetic field (GMF) for the past 10 millennia 1 . This type of material acquires a thermoremanent magnetization (TRM) at the time of its heating and subsequent cooling that is proportional to the ancient GMF intensity, or archaeointensity. This TRM is dependent on many factors including the ancient heating temperature, the type of magnetic mineral carrying the magnetization, and the reheating process.Since the beginning of archaeomagnetism, retrieving archaeointensities has been considered a demanding process. Several methods have been developed, for example the thermal Thellier-family methods 2-4 , the microwave technique 5,6 , the multispecimen methods 7,8 and non-heating methods 9,10 . One of the non-heating methods, the relative pseudo-Thellier technique 11 , makes use of alternating magnetic fields to demagnetize the samples and has recently been successfully calibrated and applied to volcanic rocks 12-14 . However, the calibrated pseudo-Thellier method has never been applied to archaeological artefacts before. The Thellier-family methods are considered as the most reliable of all techniques, because they have been used since nearly 100 years and include many quality assessments. These methods can comprise up to 50 time-consuming heating steps. On the contrary, the pseudo-Thellier method is much faster and avoids chemical alteration of the samples.Archaeological artefacts have been collected from many locations world wide to construct palaeosecular variation curves, or reference c...

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Late-Quaternary secular variation data from Mexican volcanoes

Mahgoub

Juárez-Arriaga

Böhnel

et al. 2019

Earth and Planetary Science Letters

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Last three millennia Earth’s Magnetic field strength in Mesoamerica and southern United States: Implications in geomagnetism and archaeology

Cited by 28 publications

References 62 publications

Secular Variation of the Intensity of the Geomagnetic Field in Mexico During the First Millennium BCE

Secular Variation of the Intensity of the Geomagnetic Field in Mexico During the First Millennium BCE

Novel insights on the geomagnetic field in West Africa from a new intensity reference curve (0-2000 AD)

Late-Quaternary secular variation data from Mexican volcanoes

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